Camera system, vehicle and method for configuring light source of camera system

ABSTRACT

A camera system is provided. The camera system includes an image sensor, at least one light source, and a processing unit. The image sensor is configured to capture a plurality of images. The processing unit is configured to perform the following instructions. A plurality of reflection values on at least one subject in the captured images is acquired. A relationship between a luminance level of the light sources and a reflection level on the at least one subject is obtained. A luminance configuration is determined according to the relationship between the luminance level of the light sources and the reflection level on the at least one subject. A luminous power of at least one of the light sources is adjusted according to the luminance configuration.

CROSS REFERENCE

This application claims the benefit and priority to of U.S. ProvisionalApplication Ser. No. 62/789,532, filed on Jan. 8, 2019, and entitled“SYSTEM AND METHOD OF GLARE ELIMINATION”, which is incorporated hereinby reference in its entirety.

FIELD

The present disclosure generally relates to a camera system, a vehiclehaving a camera system and method for configuring light source on acamera system.

BACKGROUND

In recent years, face detection related application has becomeincreasingly popular, and it relied on facial features extraction fromthe captured images. Conventionally, in order to allow the night visionor insufficient lighting environment, the camera system may contain aillumination unit such as an infrared illuminator or to provide a lightsource or flashlight for illuminating the face. However, theillumination unit may induce glare in photos. Specifically, glare inphotos is caused by light bouncing off a reflective surface at an angleand into the camera. In some scenarios, eye related detection orrecognition which requires the accurate information (e.g., position,size, boundaries) of the eye, iris or pupil may be severely affected bythe glare. For instance, as shown in FIG. 1, when a camera 10 captures afacial image of a person who is wearing glasses 30, the flashlightemitted by the illuminator or flash unit 20 falls on the surface of theglasses 30 and then reflects into the camera 10. Consequently, a glare70 is captured on the image. Since the glare may appear near the eyes,the position, size, or boundaries of the eye/iris/pupil may not beclearly detected or identified. As a result, any eyedetection/recognition or other recognitions therefore relied upon mayfail. Moreover, the accuracy rate of the eye recognition or otherrecognitions relied upon may be affected by the glare.

SUMMARY

In one aspect of the present disclosure, a camera system is provided.The camera system includes an image sensor, at least one light source,and a processing unit. The image sensor is configured to capture aplurality of images. The processing unit is configured to perform thefollowing instructions. A plurality of reflection values on at least onesubject in the captured images is acquired. A relationship between aluminance level of the light sources and a reflection level on the atleast one subject is obtained. A luminance configuration is determinedaccording to the relationship between the luminance level of the lightsources and the reflection level on the at least one subject. A luminouspower of at least one of the light sources is adjusted according to theluminance configuration.

In another aspect of the present disclosure, a method for configuringlight source of a camera system is provided. The method includes thefollowing actions. A plurality of images are captured. A plurality ofreflection values on at least one subject in the captured images isacquired. A relationship between a luminance level of the light sourcesand a reflection level on the at least one subject is obtained. Aluminance configuration is determined according to the relationshipbetween the luminance level of the light sources and the reflectionlevel on the at least one subject. A luminous power of at least one ofthe light sources is adjusted according to the luminance configuration.

In yet another aspect of the present disclosure, a vehicle is provided.The vehicle includes an image sensor, at least one light source, and aprocessing unit. The image sensor is configured to capture a pluralityof images. The processing unit is configured to perform the followinginstructions. A plurality of reflection values on at least one subjectin the captured images is acquired. A relationship between a luminancelevel of the light sources and a reflection level on the at least onesubject is obtained. A luminance configuration is determined accordingto the relationship between the luminance level of the light sources andthe reflection level on the at least one subject. A luminous power of atleast one of the light sources is adjusted according to the luminanceconfiguration.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic diagram of a glare appears on the glasses due tothe flash unit of a camera system.

FIG. 2 is a block diagram of a camera system 100 according to anembodiment of the present disclosure.

FIGS. 3A-3C are schematic diagrams showing various forbidden regions ofa camera system according to an embodiment of the present disclosure.

FIG. 4 is a schematic diagram shows a camera system disposed in avehicle according to an embodiment of the present disclosure.

FIG. 5 is a flowchart of a method for configuring light source of acamera system according to an embodiment of the present disclosure.

FIG. 6 is a schematic diagram of the configuration of the camera systemaccording to an implementation of the present disclosure.

FIGS. 7A and 7B are schematic diagrams of an image captured by thecamera system according to an implementation of the present disclosure.

DETAILED DESCRIPTION

The following description contains specific information pertaining toexemplary implementations in the present disclosure. The drawings in thepresent disclosure and their accompanying detailed description aredirected to merely exemplary implementations. However, the presentdisclosure is not limited to merely these exemplary implementations.Other variations and implementations of the present disclosure willoccur to those skilled in the art. Unless noted otherwise, like orcorresponding elements among the figures may be indicated by like orcorresponding reference numerals. Moreover, the drawings andillustrations in the present disclosure are generally not to scale, andare not intended to correspond to actual relative dimensions.

A camera system is proposed in this disclosure to resolve the aboveissues. FIG. 2 is a block diagram of a camera system 100 according to anembodiment of the present disclosure. The camera system 100 includes animage sensor 110, multiple light sources 120 and a processing unit 130.

The image sensor 110 is configured to capture images. In oneimplementation, the image sensor 110 may be an RGB color sensor or aninfrared (IR) sensor. The image sensors could be the charge-coupleddevice (CCD) or the active-pixel sensor (CMOS sensor).

The light sources 120 is configured to illuminate a subject to captureby the image sensor 110. In one implementation, the light sources 120may be visible light sources, or IR light sources.

The processing unit 130 is coupled to the image sensor 110 and the lightsources 120. The processing unit 130 may be a hardware module comprisingone or more central processing unit (CPU), microcontroller(s), ASIC, ora combination of above but is not limited thereof. The processing unit130 may process data and instructions. In one embodiment, the processingunit 130 is configured to identify the captured image, render images andperform image processing and biometric recognition on the capturedimages. In another embodiment, the processing unit 130 is configured tocontrol the luminance of the light sources 120.

The camera system 100 further includes a lens unit configured to providean optical path to the image sensor 110. The camera system may furtherinclude filters, circuitry or other components familiar to those ofskill in the art and thus is omitted.

In one embodiment, a vehicle is equipped with the camera system 100. Theimage sensor 110, the light sources 120, and the processing unit 130 maybe integrated in a device. Alternatively, the image sensor 110, thelight sources 120, and the processing unit 130 is disposed separatelyinside a vehicle, and each component may communicate each other viaphysical connection or wireless connection. In one implementation, theprocessing unit 130 is one of the functional modules of an automotiveelectronic control unit (ECU).

In the present disclosure, one way to resolve the issue of glare is byadjusting the arrangement of the camera system 100 (including the lightsources 120 and the image sensor 110). Precisely, a forbidden regionwhere the camera system 100 should not be disposed within is defined asfollow.

FIG. 3A is a schematic diagram showing a forbidden region Z1 of a camerasystem 200 according to an embodiment of the present disclosure. Whenthe camera system 200 is disposed within the forbidden region, a glaremay occur on the captured images. As illustrated, in order to capture aclearer image, the light source 220 is used to illuminate on the subjectto be captured (e.g., a face of a person). However, some lights emittedfrom the light source 220 may reflect directly to the image sensor 210and thus causes glare on the facial image. As shown in FIG. 3A, theincident light emitted from the light source 220 falls on the glasses230 with an incident angle θ_(a) and then reflects to the image sensor210 with the reflection angle θ_(a). The existence of glare on theglasses 230 makes the determination of the person's eyes difficult.Therefore, the arrangement of the camera system 200 in the forbiddenregion Z1 should be avoided.

People familiar with optics should understand that the glare(reflection) is dependent to the surface of the glasses 230 and therelative positions of the light source 220, the image sensor 210 and theglasses 230. Specifically, the incident angle θ_(a) could be calculatedaccording to the distance between the image sensor 210 and the lightsource 20 (which is usually fixed and on the same plane) and thedistance between the glasses 230 and the camera plane. Therefore, basedon the position and the size of the glasses 230 and the distance betweenthe image sensor 210 and the light source 220 (or the positions of theimage sensor 210 and the light source 220, or the angle θ_(a)), theforbidden region Z1 could be defined.

In another embodiment as depicted in FIG. 3B, assuming the person turnshis/her head right with an angle of θ_(r), and at the position of H2,the position of the surface of the glasses 230 and the relativepositions of the light source 220, the image sensor 210 and the glasses230 also change. Accordingly, the incident angle θ_(b) could becalculated according to the distance between the image sensor 210 andthe light source 220 (which is usually fixed and on the same plane) andthe distance between the glasses 230 and the camera plane. Therefore,based on the position and the size of the glasses 230 and the distancebetween the image sensor 210 and the light source 220 (or the positionsof the image sensor 210 and the light source 220, or the angle θ_(b)),the forbidden region Z2 could be defined.

Similarly, the movement of the person's head in yaw, pitch and roll axesmay also be considered when it comes to the determination of forbiddenzones. As shown in FIG. 3C, the forbidden region Z3 is defined accordingto the yaw, pitch and roll angle of the person's head.

Ideally, the camera system (including the image sensor and the lightsource) should not be disposed in the forbidden region. However, inlight of the limited space inside a vehicle, placing the camera systemwithin the forbidden zones could be inevitable.

FIG. 4 is a schematic diagram shows a camera system 400 disposed in avehicle according to an embodiment of the present disclosure. As shownin FIG. 4, the camera system 400 is disposed in front of the driverseat, and configured to capture images of a driver. The captured imagesmay be relied upon to infer the driver's eye status, or the driver'sgaze and the results are adopted to determine the driver's behaviorsand/or physical conditions (such as the degrees of fatigue, drowsiness,inattention, and distraction). It is critical to obtain the accurateeyes status. As mentioned, when the driver wears glasses, the eyesregion and eyes status may not be properly identified from the capturedimages because of glare caused by light reflections.

In the present disclosure, another way to eliminate the glare is todynamically dim the light sources. FIG. 5 is a flowchart of a method forconfiguring light source of a camera system according to an embodimentof the present disclosure. The method includes the following actions. Inaction 510, the image sensor captures multiple images. In action 520,the processing unit acquires multiple reflection values on at least onesubject in the captured images. In action 530, the processing unitobtains a relationship between a luminance level of the light sourcesand a reflection level on the at least one subject. In action 540, theprocessing unit determines a luminance configuration according to therelationship between the luminance of the light sources and thereflection level on the subject. In action 550, the processing unitadjusts a luminous power of at least one of the light sources accordingto the luminance configuration.

The method will be described as follow based on a scenario where thecamera system 100 is installed in a vehicle. However, the presentdisclosure is not limited thereto. FIG. 6 is a schematic diagram of theconfiguration of the camera system 100 according to an implementation ofthe present disclosure. As shown in FIG. 6, the light sources 120 mayinclude multiple light sources L₁-L_(N). Unlike the conventionalarrangement described above, the light sources L₁-L_(N) may be scatteredin a vehicle. Additionally, the luminous powers of the light sourcesLS1-LSN are individually configurable. By dynamically adjusting theluminous power of each light source L₁-L_(N), the glare may be reducedor avoided on the captured images. In order to find the appropriateconfiguration of luminous powers given to the light sources LS1-LSN, therelationship between the luminance level of the light sources and thereflection levels on the images must be obtained beforehand.

For instance, the relationship between the luminance level of the lightsources and the reflection level on the subject in the images could berepresented by the equation (1) shown below:

$\begin{matrix}{{{\begin{pmatrix}b_{1} \\b_{2}\end{pmatrix} + {\begin{pmatrix}a_{11} & a_{12} & \ldots & a_{1N} \\a_{21} & a_{22} & \ldots & a_{2N}\end{pmatrix} \times \begin{bmatrix}L_{1} \\\vdots \\L_{N}\end{bmatrix}}} = \begin{pmatrix}{G1} \\{G2}\end{pmatrix}},} & (1)\end{matrix}$where L₁-L_(N) represents the luminous powers of the light sourcesLS1-LSN, G1 and G2 are the reflection values measured on the subject(e.g., glasses 182 and 184), and b₁, b₂, a₁₁-a_(1N), a₂₁-a_(2N), arecoefficients. It should be noted that in the assumption, L₁-L_(N) arenon-negative real numbers, G1 and G2 are real numbers and 0≤G1≤1,0≤G2≤1, and b₁, b₂, a₁₁-a_(1N), a₂₁-a_(2N), are real numbers.

In one embodiment, the relationship could be obtained by performingexperiments applying various sets of luminous powers L₁-L_(N) andmeasuring the reflection values captured by the image sensor 110.Particularly, the processing unit 130 configures the light sources withmultiple sets of luminance values, where each set of luminance values isapplied to at least one light source at a same time. Assuming the lightsources LS1-LSN are placed under a particular arrangement and appliedwith a set of luminous powers L₁-L_(N), the reflection values of G1 andG2 that appear on the glasses 182 and 184 are measured, respectively. Inone implementation, the reflection value (e.g., G1 or G2) is 0 if thereis no reflective light observed on the subject (182 or 184); otherwisethe value is greater than 0 to indicate the occurrence of a reflectivelight. In another implementation, the reflection level could bedetermined by the degree of the brightness measured on the subject(glasses 182 or 184). In yet another implementation, the reflectionlevel may be determined by whether the subject (e.g., the eye, the iris,or the pupil) is blocked or could not be identified. For instance, thereflection level could be represented by the ratio of the size of theglare to the size of the subject. Afterwards, the processing unit 130calculates the relationship according to the multiple sets of luminancevalues and the reflection values. Based on the experimental data, thecoefficients b₁, b₂, a₁₁-a_(1N), a₂₁-a_(2N) and therefore therelationship (equation) can substantially obtained based on the currentarrangement of the light sources LS1-LSN.

In another embodiment, the relationship could be obtained by performingdeep-learning, machine learning or similar techniques familiar by theskilled persons and acquired beforehand. For instance, the relationshipcould be represented by another equation (2): B+A×L=G, where L is theluminance level of the light sources, G is the reflection level on thesubject, and B and A are matrices or functions substantially acquired bythe machine learning or deep-learning or similar techniques.

In addition, the relationship (equation) based on different arrangementsof the light sources LS1-LSN could be obtained through similar process.

After the relationship (equation) is obtained, the processing unit 130could obtain the suitable luminous power of each light source LS1-LSNthat reduce or minimize the reflection values and configure the lightsource LS1-LSN accordingly to reduce the glare. As such, the camerasystem 100 may reduce the glare by dimming the light source 120 eventhough the camera system 100 is disposed in the region where the glaremight be induced.

Since the camera system 100 can dynamically adjust the luminous powersof the light sources based on the reflection level of the reflectivelights, it would also work even if the person changes the head position.For instance, the processing unit 130 could keep tracking the driver'sactions (including head movement or eye movement) and the correspondingreflection values and thus, even if the driver moves his head or eyes,the processing unit 130 could adjust the luminous power of the lightsource LS1-LSN to reduce the glare. In one implementation, therelationship (equation) is established further according to the driver'sactions (including head movement or eye movement).

In some embodiments, even if the glare is not caused by the lightsources of the camera system 100 but other environment light or ambientlight such as sunlight, ceiling lights, and lamps, the camera system 100can also eliminate it by dynamically adjusting the luminous powers ofthe light sources. Specifically, the processing unit 130 apply varioussets of luminous powers L₁-L_(N) and measure multiple reflection valueson the subject. Next, the processing unit 130 obtain the relationshipbetween the luminance level of the light sources and the reflectionlevel on the subject based on the experimental data. Based on therelationship, the processing unit 130 obtain the suitable luminous powerof each light source LS1-LSN that minimize the reflection values andconfigure the light source LS1-LSN accordingly to reduce the glare.

It should be noted that, although that the above example is illustratedwith respect to an image capturing a person wearing glasses. However,the present disclosure is not limited thereto. Reflection from otherobjects (e.g., glass objects, windows, mirrors, and even water) couldalso cause glare. Hence, as long as the identification of a subject isaffected by the glare, the processing unit 130 adjusts the luminouspower of the light sources according to the luminance configuration.

In one implementation, the processing unit 130 identifies the subjectfrom the captured images and determine whether a glare is on thesubject. For instance, the processing unit 130 identifies the eyesregion of a person from the captured images, and determine whether thereis a glare on the eye region. When it is determined that the glare is onthe eye region, the processing unit 130 adjusts the luminous power ofthe light sources according to the luminance configuration. As a result,the light sources could be configured with proper luminous powers suchthat the subject could be properly identified.

In another implementation, the glare may be too large or too strong thatthe subject may not be detected at all. Thus, as long as a glare isdetected on the captured image, the processing unit 130 adjusts theluminous power of the light sources according to the luminanceconfiguration. In addition, the processing unit 130 may furtherdetermine whether the identification of the subject is affected by theglare according to, for example, the position of the glare in the imagesor the size of the glare. When it is determined that the identificationof the subject is affected by the glare, the processing unit 130 adjuststhe luminous power of the light sources according to the luminanceconfiguration.

It should be noted that, according to the relationship (equation), theremight be multiple configuration of luminous power L₁-L_(N) (solution ofthe equation) that reduce or minimize the reflection values G1 and G2(glare). In one implementation, the luminance configuration isdetermined according to a condition that an overall luminance exceeds athreshold. In other words, the overall luminous power of the lightsources LS1-LSN is adjusted such that the captured image is sufficientlybright enough for any subsequent image processing and/or recognition.For instance, the overall luminous power L_(A) should satisfy thefollowing condition (3): |L_(A)|=√{square root over (L₁ ²+L₂ ²+ . . .+L_(N) ²)}>BS_(th), where L₁-L_(N) are the luminance powers of the lightsources, and they are non-negative real numbers; and BS_(th) is theminimum luminous power that a scene requires and is a non-negative realnumber.

In another implementation, the luminance configuration is determinedaccording to a condition that an overall brightness on the capturedimages exceeds a threshold which is the minimum brightness of the imagesfor any subsequent image processing and/or recognition. For instance,the relationship between the luminance level of the light sources and abrightness level on the captured images could be represented by theequation (4): C×L=B, where L is the luminance level of the lightsources, B is the brightness level on the captured images, and C ismatrix or function substantially acquired by the machine learning ordeep-learning or similar techniques. Alternatively, the matrix orfunction C is deduced by experiments.

In yet another implementation, the luminance configuration is determinedaccording to a condition that the reflection level on the at least onesubject is reduced. For instance, when the reflection level indicatingthe degree of the brightness measured on the subject is reduced to acertain level, the processing unit 130 may identify the subjectproperly. Alternatively, when the reflection level represented by theratio of the size of the glare to the size of the subject is reduced,the processing unit 130 may identify the subject properly.

In some other embodiments, the uniformity of brightness is furtherconsidered. FIGS. 7A and 7B are schematic diagrams of an image capturedby the camera system 100 according to an implementation of the presentdisclosure. As shown in FIG. 7A, a bounding box 660 of a person's facein the image is detected. As shown in FIG. 7B, the bounding box 660 maybe divided into multiple regions (e.g., N×M, where N, M are positiveintegers). The brightness value of each region (e.g., B_(ij)) ismeasured. In order to make the captured image free of obvious hotspotsor unintended dark areas, the processing unit 130 may take a furtherstep to adjust the luminance powers of the light source LS1-LSN tominimize the brightness divergence formed in each of the regions.

For instance, the relationship between the luminance level of the lightsources and a brightness level on the captured images is represented bythe following equation (5):

${{\begin{pmatrix}c_{11} & \; & \; & \ldots & c_{1N} \\\; & \vdots & \; & \ddots & \vdots \\c_{{({N*M})}1} & \; & c_{{({N*M})}2} & \ldots & c_{{({N*M})}N}\end{pmatrix} \times \begin{bmatrix}L_{1} \\\vdots \\L_{N}\end{bmatrix}} = \begin{bmatrix}B_{11} \\\vdots \\B_{N*M}\end{bmatrix}},$where L₁-L_(N) represents the luminance powers of the light sourcesLS1-LSN, B₁₁, B₁₂, . . . , B_(1M), B₂₁, B₂₂, . . . , B_(2M), . . . ,B₃₁, . . . , B_(ij), . . . , B_(N1), . . . B_(NM), are brightness valuesof each region and is a real number and 0<B_(ij)≤1, and c₁₁, . . . ,c_((N*M)1), c_((N*M)2), . . . , c_((N*M)N) are real numbers.

The relationship between the luminance level of the light sources andthe brightness level on the captured images could be obtained byperforming experiments. Specifically, apply various sets of luminouspowers L₁-L_(N) and measure multiple brightness values of each region(e.g., B_(ij)). Next, obtain the relationship between the luminancelevel of the light sources and the brightness level on the capturedimages based on the experimental data. Alternatively, the relationshipcould be obtained by performing deep-learning, machine learning orsimilar techniques familiar by the skilled persons and acquiredbeforehand.

In one implementation, the luminance configuration is determinedaccording to a condition that a brightness uniformity on the capturedimages is below a threshold. For example, the brightness gradient BG maybe represented by the following equation (6):BG=(B ₁₁ −B ₁₂)²+(B ₁₂ −B ₁₃)² . . . +(B _(N*M-1)) −B _(NM))²+(B ₁₁ −B₂₁)²+(B ₂₁ −B ₃₁)²+ . . . +(B _((N-1)M) −B _(NM))²,where B₁₁, . . . , B_(NM) are brightness values of each region and is areal number, and 0<B_(ij)≤1.

After the relationship (equation) is obtained, the processing unit 130could obtain the suitable luminous power of each light source LS1-LSNsuch that the brightness gradient BG on the captured images is reducedor minimized and then configure the light source LS1-LSN accordingly tothus make the brightness more uniform.

Based on the above, the present disclosure provides a camera system, amethod for configuring light sources of a camera system, and a vehicle.By dynamically dimming the light sources, the glare could be reducedeven though the camera system and the light sources are disposed in theforbidden regions where glare may occur. Moreover, the luminous power ofthe light sources could also be dynamically adjusted based on thedriver's instant position. In addition, another advantage brought byadjustable light sources is the quality of the captured images areenhanced with respect to the brightness and uniformity, and thereforeany image recognitions based upon are more accurate.

Based on the above, several camera systems, methods for configuringlight sources of a camera system, and vehicles are provided in thepresent disclosure. The implementations shown and described above areonly examples. Even though numerous characteristics and advantages ofthe present technology have been set forth in the foregoing description,together with details of the structure and function of the presentdisclosure, the disclosure is illustrative only, and changes may be madein the detail, including in matters of shape, size and arrangement ofthe parts within the principles of the present disclosure up to, andincluding, the full extent established by the broad general meaning ofthe terms used in the claims.

What is claimed is:
 1. A camera system, comprising: an image sensorconfigured to capture a plurality of images; a plurality of lightsources; and a processing unit coupled to the image sensor and the lightsources, wherein the processing unit is configured to performinstructions for: acquiring a plurality of reflection values on at leastone subject in the captured images; obtaining a relationship between aluminance level of the light sources and a reflection level on the atleast one subject; determining a luminance configuration according tothe relationship between the luminance level of the light sources andthe reflection level on the at least one subject; and adjusting aluminous power of at least one of the light sources according to theluminance configuration.
 2. The camera system of claim 1, wherein theprocessing unit is further configured to perform instructions for:identifying the at least one subject from the captured images; anddetermining whether a glare is on the at least one subject; wherein theluminous power of the at least one of the light sources is adjustedaccording to the luminance configuration when it is determined that theglare is on the at least one subject.
 3. The camera system of claim 1,wherein the processing unit is further configured to performinstructions for: determining whether a glare is on at least one of thecaptured images; wherein the luminous power of the at least one of thelight sources is adjusted according to the luminance configuration whenan identification of the at least one subject is affected by the glare.4. The camera system of claim 1, wherein the processing unit is furtherconfigured to perform instructions for: configuring the light sourceswith multiple sets of luminance values, wherein each set of luminancevalues is applied to at least one light source at a same time; whereineach reflection value on the at least one subject is acquired when eachset of luminance values is applied to the at least one light source atthe same time; and the relationship is calculated according to themultiple sets of luminance values and the reflection values.
 5. Thecamera system of claim 1, wherein the luminance configuration isdetermined according to a condition that an overall luminance exceeds athreshold.
 6. The camera system of claim 1, wherein the luminanceconfiguration is determined according to a condition that an overallbrightness on the captured images exceeds a threshold.
 7. The camerasystem of claim 1, wherein the luminance configuration is determinedaccording to a condition that the reflection level on the at least onesubject is reduced.
 8. The camera system of claim 1, wherein theluminance configuration is determined according to a condition that abrightness uniformity on the captured images is below a threshold. 9.The camera system of claim 8, wherein the processing unit is furtherconfigured to perform instructions for: obtaining multiple brightnessvalues on multiple regions of the captured images, wherein eachbrightness value is obtained corresponding to each region on eachcaptured image; and obtaining a relationship between the luminance levelof the light sources and a brightness level on the captured images;wherein the luminance configuration is further determined according to acondition that a brightness gradient on the captured images is reduced.10. A method for configuring light source of a camera system,comprising: capturing, by an image sensor, a plurality of images;acquiring, by a processing unit, a plurality of reflection values on atleast one subject in the captured images; obtaining, by the processingunit, a relationship between a luminance level of the light sources anda reflection level on the at least one subject; determining, by theprocessing unit, a luminance configuration according to the relationshipbetween the luminance of the light sources and the reflection level onthe subject; and adjusting, by the processing unit, a luminous power ofat least one of the light sources according to the luminanceconfiguration.
 11. The method of claim 10, further comprising:identifying, by the processing unit, the at least one subject from thecaptured images; and determining, by the processing unit, whether aglare is on the at least one subject; wherein the luminous power of theat least one of the light sources is adjusted according to the luminanceconfiguration when it is determined that the glare is on the at leastone subject.
 12. The method of claim 10, further comprising:determining, by the processing unit, whether a glare is on at least oneof the captured images; wherein the luminous power of the at least oneof the light sources is adjusted according to the luminanceconfiguration when an identification of the at least one subject isaffected by the glare.
 13. The method of claim 10, further comprising:configuring, by the processing unit, the light sources with multiplesets of luminance values, wherein each set of luminance values isapplied to at least one light source at a same time; wherein eachreflection value on the at least one subject is acquired when each setof luminance values is applied to the at least one light source at thesame time; and the relationship is calculated according to the multiplesets of luminance values and the reflection values.
 14. The method ofclaim 10, wherein the luminance configuration is determined according toa condition that an overall luminance exceeds a threshold.
 15. Themethod of claim 10, wherein the luminance configuration is determinedaccording to a condition that an overall brightness on the capturedimages exceeds a threshold.
 16. The method of claim 10, wherein theluminance configuration is determined according to a condition that thereflection level on the at least one subject is reduced.
 17. The methodof claim 10, wherein the luminance configuration is determined accordingto a condition that a brightness uniformity on the captured images isbelow a threshold.
 18. The method of claim 17, further comprising:obtaining, by the processing unit, multiple brightness values onmultiple regions of the captured images, wherein each brightness valueis obtained corresponding to each region on each captured image; andobtaining, by the processing unit, a relationship between the luminancelevel of the light sources and a brightness level on the capturedimages; wherein the luminance configuration is determined according to acondition that a brightness gradient on the captured images is reduced.19. A vehicle, comprising: an image sensor configured to capture aplurality of images; a plurality of light sources; and a processing unitcoupled to the image sensor and the light sources, wherein theprocessing unit is configured to perform instructions for: acquiring aplurality of reflection values on at least one subject in the capturedimages; obtaining a relationship between a luminance level of the lightsources and a reflection level on the at least one subject; determininga luminance configuration according to the relationship between theluminance level of the light sources and the reflection level on the atleast one subject; and adjusting a luminous power of at least one of thelight sources according to the luminance configuration.
 20. The vehicleof claim 19, wherein the processing unit is further configured toperform instructions for: determining whether a glare is on at least oneof the captured images; wherein the luminous power of the at least oneof the light sources is adjusted according to the luminanceconfiguration when an identification of the at least one subject isaffected by the glare.